Screen frame fixture



July 31, 1962 H. N. WILCOX ETAL SCREEN FRAME FIXTURE Filed Jan. 7, 1959 FIG. 2

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Mwp W United States Patent 3,047,061 SCREEN FRAME FIXTURE Harvey N. Wilcox, Chicago, and Donald P. Smith,

Wheaten, Ill., assignors to Commercim Picture Equipment, Inc, Chicago, 111., a corporation of Illinois Filed Jan. 7, 1959, Ser. No. 785,487 3 Claims. (Cl. 160-351) The present invention relates to an improved frame supporting fixture for a picture projection screen.

In order to adjust the height of portable motion picture screens to accommodate the screen to the environment in which it may find use, it has been customary to provide means for adjustably interconnecting the uprights supporting the screen and the screen frame. Although tures employing a friction locking device which permit infinite variation in the adjusted height of the screen, within the practical limits of the uprights, are most desirable, the fixtures of this type known in the past have not been satisfactory. The friction lock has either failed to support the weight of the screen frame and screen, or if designed to overcome this limitation, the set or lock screws used to develop the friction between screen frame and upright have imposed localized stresses on the uprights damaging the uprights. Consequently, resort has been made to other means for supporting the larger sized portable screens. One common means includes studs which are fixed to the ends of the frame and which are engageable with apertures cut into the uprights at regularly spaced intervals. This type of arrangement limits the height adjustment to the predetermined positions at which the apertures are provided on the uprights. Also, cutting a plurality of slots in the upright tends to Weaken the upright as well as increase its cost of manufacture.

It is an object of the present invention to provide an improved fixture of the friction lock type which overcomes the limitations of prior known devices of this general type.

The'improved fixture may be described generally as having a first bracket portion for engaging the screen frame and a second bracket portion for receiving the upright. The second bracket portion is equipped with an improved friction lock by means of which the fixture may be firmly fixed relative to the uprights supporting the screen frame at any height desired.

In the single sheet of drawings accompanying the specification:

FIG. 1 is a perspective view of a screen frame, a pair of screen uprights and the improved fixture showing the interrelation of the three;

FIG. 2 is a perspective view of the improved fixture and a segment of the screen frame illustrating a preferred means of removably attaching the fixture to the screen frame;

FIG. 3 is a plan view in section of the fixture; and

FIG. 4 is taken along the line 4-4 of FIG. 3.

Referring to the drawings and first to FIG. 1, a screen frame is shown supported upon a pair of uprights partially shown at 11, 11 by the improved fixtures 12, 12. The fixtures 12, 12 are not adjustable with respect to the screen frame 10. They are attached to the sides of the frame 10 at or above the mid-point of the side members 13, 13 of the frame 10 and are each positioned an equal distance from the top of the frame.

The screen frame 10 and the uprights 1'1, 11 are fabricated of extruded aluminum so as to be strong yet light in weight. The frame and uprights illustrated are square in cross-section. This configuration readily lends itself to the structures herein described. However, the crosssectional configuration is not controlling, and the geometry of the fixture may be varied to accommodate uprights and screen frames having other cross-sectional shapes.

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The improved fixture is shown in detail in FIGS, 2, 3, and 4. Turning now to these figures, it will be noted that the fixture 12 is relatively high so as to engage both screen frame 10 and upright 11 firmly and securely along a substantially long portion of each. As best seen in FIG. 2, the fixture 12 is made up of two bracket portions designated generally by the reference numerals 14 and 15. The bracket 14 is U-shaped in horizontal cross-section and fits about three sides of the screen frame segment 16. The bracket 14 may be permanently afiixed to the screen frame, but, preferably, the two are removably joined. As shown in FIG. 2, this is accomplished by providing, in the side of the U-shaped bracket 14, an upper slot 17 and a lower slot 18. The upper slot 17 is positioned vertically and opens to the top of bracket portion 14. The lower slot 18 is a compound slot having a horizontal section opening to the inner face 19 of the bracket 14 and merging at its opposite end with a vertical section. The upper slot 17 and the vertical section of the lower slot 18 are aligned one with the other and are each parallel to the inner face 19 of the bracket 14. Each of the slots 17 and 18 are engageable with identical upper and lower pins 20 and 21, respectively, extending through the frame segment 16 so as to engage identical slots 17 and 18 cut in the opposite wall of bracket 14 (FIG. 3).

The frame segment 16 and fixture 12 may be disengaged by lifting the frame segment 16 relative to the fixture 12, which movement frees the pin 20 from the slots 17 and 17 and positions the pin 21 at the junction of the vertical and horizontal sections of slots 18 and 18 and then by moving the fixture 12 laterally away from the frame segment 16. The latter movement frees the pin 21 from the horizontal section of the slots 18 and 18 The bracket portion 15 of fixture 12 has a horizontal cross-sectional configuration identical to that of the upright 11 on which it will be received. The inner dimensions of the bracket 15 are such that the fixture 12 slips over and around the upright 11 with a slack or relaxed fit so as to permit the fixture 12 to be freely slidable axially of the upright '11 when the friction lock, to be discussed subsequently, is not engaging the upright. As here illustrated, the two bracket portions 14 and 15 have a common wall 22. This structural arrangement is not essential to the fixture, however, and indeed is not practical if the two brackets have other cross-sectional configurations than those shown, for example, semi-circular and circular,

respectively. In such case the two brackets 14 and 15 may.

be joined by any convenient means. A friction lock is fitted to the bracket 15 at its lower end. The friction lock includes a set or lock screw plate 23'fixed to the exterior of the bracket 15. The plate 23 has a drilled and tapped opening 24 therethrough for receiving the threaded end 25 of a lock screw 26. A suitably shaped, knurled knob 27 is attached to the opposite end of the lock screw 26 to facilitate manipulation of the lock screw. The face of the threaded end 25 moves into abutting engagement with a friction plate 28 as the lock screw 26 is screwed into the tapped opening 24.

The friction plate 28 is a part of the Wall 29 of bracket 15. It is formed by the parallel cuts 30, 30 (FIG. 4), of equal length, extending vertically upwardly from the bottom to a region medial of the wall 29. The friction plate 28 is thus freed on three of its sides from the wall 29, and, under the influence of the lock screw 26, it may be biased inwardly at its lower end as most easily seen in FIG. 3. As the free end of the cantilevered friction plate 28 is urged inwardly it bridges the small space resulting from the relaxed fit between bracket 15 and an upright 11 receivable within bracket 15 and comes into engagement with one wall of the upright 11. Ultimately, the lock screw 26, through the friction plate 28, may be made to force the opposite wall of the upright 11 into frictional '22 establishing a strong lock between the upright 11 and the fixture 12.

-As the friction plate 28 has an area many times greater than the area of the face of the threaded end 25 of lock screw 26 in contact with the upright 11, the force exerted by lock screw 26 on the upright 11 per unit of area is greatly reduced. The lock screw 26 may be vigorously tightened so as to exert a force of suflicient magnitude to establish a strong locking engagement for supporting the screen frame at the desired height on the uprights 11 Without fear or danger of indenting the walls of the upright 11, damaging them, and limiting futu-re utility of the upright.

We claim:

1. The combination with a picture projection screen frame and a screen frame supporting upright, of a bracket by which the screen frame is detachably supportable at selectable elevations on the upright, the bracket having an elongated opening therethrough providing a slideway through which the upright extends telescopically for adjustment of the bracket therealong, said opening being defined by bracket walls one of which has a pair of laterally spaced slits providing an elongated bendable wall portion therebetween and the bracket having a threaded member thereon which is operable to clamp said bendable wall portion against the upright to lock the bracket in selectable positions of adjustment along the upright, and the bracket having means by which a portion of the projection screen frame is detachably securable thereto in general parallelism with the upright in said opening of the bracket.

2. The combination as defined in claim 1 wherein the elongated bendable wall portion is a tongueat one end of the elongated opening and the threaded member is carried by a stirrup which has an opening through which an end portion of the bracket extends.

3. The combination with a picture projection screen frame and a screen frame supporting upright, of a bracket by which the screen frame is'detachably supportable at selectable elevations on the upright, the screen frame having an elongated rectilinear portion which is cooperable with the bracket for, detachable interengagement thereof and the bracket being provided with a pair of elongated parallel slideways which are open at their opposite ends to accommodate and hold the said elongated rectilinear portion of the screen frame and the upright respectively therein in generally parallel relation to one another, one said slideway forming a generally tubular enclosure through which the upright extends telescopically for adjustability of the bracket lengthwise of the upright and the other slideway being open at one side for reception of said elongated rectilinear portion of the screen frame sidewise therein'to a confined position of longitudinal slideability therein, said bracket having parallel opposite side walls integral with and interconnected in laterally spaced apart relation by laterally spaced intervening Walls which are disposed at one side of the open sided slideway and at the opposite sides respectively of the other slideway, one of said Walls being slitted to provide a tongue which is straddled by a yoke having an adjusting screw extending therethrough by which the tongue is adjustable to clamp the supporting upright in the slideway which forms a generally tubular enclosure.

References Cited in the file of this patent UNITED STATES PATENTS 1,059,890 McClure Apr. 22, 1913 1,584,105 Lenz May 11, 1926 2,290,874 Graft July 28, 1942 2,502,667 Pagett Apr. 4, 19

FOREIGN PATENTS 136,629 Australia Sept. 18, 1947 Great Britain Mar. 10, 1948 

